Subversion Repositories svnkaklik

Rev

Rev 354 | Go to most recent revision | Only display areas with differences | Ignore whitespace | Details | Blame | Last modification | View Log

Rev 354 Rev 358
1 
/* compass.c
 1 
/* compass.c
2 
 *
 2 
 *
3 
 * Software to read from the CMPS03 magnetic compass.
3 
 * Software to read from the CMPS03 magnetic compass.
4 
 *
 4 
 *
5 
 * By Josh Marshall, joshua dot marshall at studentmail dot newcastle dot edu dot au
 5 
 * By Josh Marshall, joshua dot marshall at studentmail dot newcastle dot edu dot au
6 
 * October 15, 2004.
 6 
 * October 15, 2004.
7 
 *
 7 
 *
8 
 * Adapted from code for the SP03 speech synthesiser
8 
 * Adapted from code for the SP03 speech synthesiser
9 
 * By Bram Stolk, b.stolk at chello.nl
 9 
 * By Bram Stolk, b.stolk at chello.nl
10 
 *
 10 
 *
11 
 * Bram Stolk's notes:
 11 
 * Bram Stolk's notes:
12 
 * In linux, you can do I2C stuff in user-space, if you enable
 12 
 * In linux, you can do I2C stuff in user-space, if you enable
13 
 * the device-interface to i2c. You can use plain read() and
13 
 * the device-interface to i2c. You can use plain read() and
14 
 * write() calls on your /dev/i2c-0 file.
 14 
 * write() calls on your /dev/i2c-0 file.
15 
 *
 15 
 *
16 
 * NOTE: Check if you have an i2c adapter active by doing:
 16 
 * NOTE: Check if you have an i2c adapter active by doing:
17 
 * cat /proc/bus/i2c
 17 
 * cat /proc/bus/i2c
18 
 * If this comes up empty, then you have no adapters. If the
 18 
 * If this comes up empty, then you have no adapters. If the
19 
 * file does not exist at all, you probably lack i2c kernel
 19 
 * file does not exist at all, you probably lack i2c kernel
20 
 * support alltogether.
 20 
 * support alltogether.
21 
 */
 21 
 */
22 
 
 22 
 
23 
#include <errno.h>
 23 
#include <errno.h>
24 
#include <string.h>
 24 
#include <string.h>
25 
#include <stdio.h>
 25 
#include <stdio.h>
26 
#include <stdlib.h>
 26 
#include <stdlib.h>
27 
#include <unistd.h>
 27 
#include <unistd.h>
28 
#include <fcntl.h>
 28 
#include <fcntl.h>
29 
#include <linux/i2c-dev.h>
 29 
#include <linux/i2c-dev.h>
30 
 
 30 
 
31 
/* Note that the documentation for the compass states its address as 0xC0.
 31 
/* Note that the documentation for the compass states its address as 0xC0.
32 
 * However, this includes the low bit which specifies read or write.
 32 
 * However, this includes the low bit which specifies read or write.
33 
 * Linux i2c does not include this bit in this address, so the actual
 33 
 * Linux i2c does not include this bit in this address, so the actual
34 
 * address is 0xC0 shifted down, 0x60.
 34 
 * address is 0xC0 shifted down, 0x60.
35 
 */
 35 
 */
36 
#define CMPS03_ADDR 0x60
 36 
#define CMPS03_ADDR	0x60
- 
 
 37 
#define I2C_SLAVE	0x0B	/* Change slave address
37 
 
 38 
 
38 
/* The important registers on the compass. Internal/test registers omitted. */
 39 
/* The important registers on the compass. Internal/test registers omitted. */
39 
#define CMPS03_SOFTWARE_REVISION 0x0
 40 
#define CMPS03_SOFTWARE_REVISION 0x0
40 
#define CMPS03_BEARING_BYTE 0x1
 41 
#define CMPS03_BEARING_BYTE 0x1
41 
#define CMPS03_BEARING_WORD_HIGH 0x2
 42 
#define CMPS03_BEARING_WORD_HIGH 0x2
42 
#define CMPS03_BEARING_WORD_LOW 0x3
 43 
#define CMPS03_BEARING_WORD_LOW 0x3
43 
#define CMPS03_CALIBRATE_CMD 0xF
 44 
#define CMPS03_CALIBRATE_CMD 0xF
44 
 
 45 
 
45 
int main(int argc, char *argv[]) {
 46 
int main(int argc, char *argv[]) {
46 
   char *end;
 47 
   char *end;
47 
   int res,file;
 48 
   int res,file;
48 
   int e1;
 49 
   int error;
49 
   char filename[20] ;
 50 
   char filename[20] ;
50 
   long funcs;
 51 
   long funcs;
51
52
52 
   int heading_byte, heading_word_h, heading_word_l;
 53 
   int heading_byte, heading_word_h, heading_word_l;
53 
   int bearing_long, bearing_degrees;
 54 
   int bearing_long, bearing_degrees;
54
55
55 
   sprintf(filename,"/dev/i2c-%d");
 56 
   sprintf(filename,"/dev/i2c-0");
56 
   if ((file = open(filename,O_RDWR)) < 0) {
 57 
   file = open(filename,O_RDWR);
- 
 
 58 
   if (errno != 0)
- 
 
 59 
   {
57 
     e1 = errno;
 60 
     switch (errno)
- 
 
 61 
     {
58 
     if (e1 != ENOENT) {
 62 
     case EACCES:
59 
       fprintf(stderr,"Error: Could not open file '%s' : %sn",
 63 
         fprintf(stderr,"Run as root? \n");
60 
               filename,strerror(e1));
 64 
         break;
61 
       if(e1 == EACCES)
 65 
     default:
62 
         fprintf(stderr,"Run as root?n");
 66 
         fprintf(stderr,"Error: Could not open file '%s' : %s \n", filename, strerror(errno));
- 
 
 67 
         break;
63 
     }
 68 
     }
64 
   }
69 
   }
65
70
66 
   if (ioctl(file,I2C_SLAVE,CMPS03_ADDR) < 0) {
 71 
   if (ioctl(file,I2C_SLAVE,CMPS03_ADDR) < 0) {
- 
 
 72 
     switch (errno)
- 
 
 73 
     {
67 
     if (errno == EBUSY) {
 74 
     case EBUSY:
68 
       printf("device is busyn");
 75 
         printf("device is busy \n");
- 
 
 76 
         break;
- 
 
 77 
 
69 
     }
 78 
     default:
70 
     printf("Got error: %d\n", errno);
 79 
         printf("Got error: %s \n", strerror(errno));
71 
     exit(0);
 80 
         exit(0);
- 
 
 81 
      }
72 
   }
 82 
   }
73
83
74 
   /* Get software revision number */
 84 
   /* Get software revision number */
75 
   res = i2c_smbus_read_byte_data(file, CMPS03_SOFTWARE_REVISION);
 85 
   res = read(file, CMPS03_SOFTWARE_REVISION,1);
76 
   if (res < 0) {
 86 
   if (res < 0) {
77 
     printf("Cannot read software revision leveln");
 87 
     printf("Cannot read software revision level \n");
78 
   } else {
 88 
   } else {
79 
     printf("Software revision level: %02xn", res);
 89 
     printf("Software revision level: %02x \n", res);
80 
   }
 90 
   }
81
91
82 
   /* Loop and read from the compass. */
 92 
   /* Loop and read from the compass. */
83 
   while (1) {
 93 
   while (1) {
84 
     /* The heading byte is 0-255 for the 360 degrees. */
 94 
     /* The heading byte is 0-255 for the 360 degrees. */
85 
     heading_byte = i2c_smbus_read_byte_data(file, CMPS03_BEARING_BYTE);
 95 
     heading_byte = read(file, CMPS03_BEARING_BYTE,1);
86 
     if (heading_byte < 0) { printf("Error reading from compass."); exit(1);}
 96 
     if (heading_byte < 0) { printf("Error reading from compass. \n"); exit(1);}
87
97
88 
     /* The high resolution heading is given in two registers, and is 10 * the
98 
     /* The high resolution heading is given in two registers, and is 10 * the
89 
      * heading in degrees, ie 359.9 degrees reads as 3599. */
 99 
      * heading in degrees, ie 359.9 degrees reads as 3599. */
90 
     heading_word_h = i2c_smbus_read_byte_data(file, CMPS03_BEARING_WORD_HIGH);
 100 
     heading_word_h = read(file, CMPS03_BEARING_WORD_HIGH,1);
91 
     if (heading_word_h < 0) { printf("Error reading from compass."); exit(1);}
 101 
     if (heading_word_h < 0) { printf("Error reading from compass. \n"); exit(1);}
92 
     heading_word_l = i2c_smbus_read_byte_data(file, CMPS03_BEARING_WORD_LOW);
 102 
     heading_word_l = read(file, CMPS03_BEARING_WORD_LOW,1);
93 
     if (heading_word_l < 0) { printf("Error reading from compass."); exit(1);}
 103 
     if (heading_word_l < 0) { printf("Error reading from compass. \n"); exit(1);}
94
104
95 
     /* Combine the two bytes, and get the heading in degrees. */
 105 
     /* Combine the two bytes, and get the heading in degrees. */
96 
     bearing_long = heading_word_h * 256 + heading_word_l;
 106 
     bearing_long = heading_word_h * 256 + heading_word_l;
97 
     bearing_degrees = bearing_long / 10;
 107 
     bearing_degrees = bearing_long / 10;
98
108
99 
     printf("Bearing: %d \n", bearing_degrees);
 109 
     printf("Bearing: %d \n", bearing_degrees);
100
110
101 
     /* Wait for a while. */
 111 
     /* Wait for a while. */
102 
     usleep(200000);
 112 
     usleep(200000);
103 
   }
 113 
   }
104 
}
 114 
}